This application claims the priority of Japanese Patent Applications No. 2000-298659 filed on Sep. 29, 2000 which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a structure of an endoscope tip part, and particularly, to the structure of an endoscope tip part whose diameter is decreased for making the insertion into an observed body easy.
2. Description of the Prior Art
In FIG. 5 and FIG. 6, a configuration of a tip part of a conventional endoscope apparatus is shown, and at a tip part 1, a lens barrel 3 of an object optical system, a treating device inserting channel (pipe) 4, or a light guide 5 is arranged in a mounting hole of an internal support body 2. To the above described lens barrel 3, an optical part holding fixture 6 which includes this lens barrel 3 and contains an optical member such as an optical filter is provided, and to this optical part holding fixture 6, a prism 7 is optically connected, and to this prism 7, a CCD (Charge CoupledDevice) (or a CCD package) 8 is bonded.
Then, to the above described support body 2, a cap 9 made of synthetic resin is attached on the tip side thereof, and in the meantime, on the rear end side, a sleeve 10 is connected, and on the outer periphery of these sleeve 10 and support body 2, an outer skin 11 made of rubber is covered. That is, at the outer peripheral part of the above described support body 2, a step part 2A which goes inside from the same position as the outer peripheral position of the sleeve 10 is formed, and the end part of the outer skin 11 arranged at this step part 2A is wound by a string, and on this string winding part 12, adhesives 13 or the like are applied, so that the outer skin 11 is fixed.
Thus, to the tip part 1, the object optical system including the lens barrel 3, the treating device inserting channel 4, and the light guide 5 or the like are arranged at specified positions, and in the meantime, the outer periphery of this tip part 1 is covered by the cap 9 made of synthetic resin and the outer skin 11 made of rubber. Then, by these cap 9 and outer skin 11, the electrical insulation can be ensured between the interior and the exterior in the endoscope.
However, in the case of the above described endoscope tip pat, as shown in FIG. 5, the thickness is thin at part of the step part 2A, and from the point of view of ensuring the strength of the support body 2, it is impossible to make this step part 2A deep, and therefore, the circumferential part of the above described string winding part 12 and adhesives 13 that is the fixing part of the outer skin 11 a little swells as shown in the drawing, and there has been such a problem that the reduction of the diameter of the endoscope tip part 1 is prevented, and that the easiness of insertion thereof is affected.
That is, conventionally, the reduction of the diameter of the tip part (insertion part) 1 has been tried by planning the shape of each internal member and the arrangement thereof, but if the circumferential part of the fixing part of the above described outer skin 11 swells, the diameter is increased as a result by the amount corresponding thereto. Furthermore, the smooth insertion of the tip part 1 is prevented more badly as the difference between this swell part (outer skin fixing part) and the outside diameter of the outer skin 11 becomes larger.
The present invention is achieved in view of the above described problems, and it is an object thereof to provide an endoscope tip part in which the swell of the outer skin fixing part at the tip part is eliminated, and the reduction of the diameter and the easiness of insertion of the endoscope are not prevented.
In order to attain the above described object, the present invention includes: a lens barrel provided to an endoscope tip part; an optical part holding fixture which is fitted on the outer peripheral rear side of the above described lens barrel for connecting an optical member to this lens barrel; a tip part support member having a mounting hole where the above described lens barrel is fitted and arranged; and a recess (for example, a step part or a fixing groove) which is formed like a ring on the outer periphery of this tip part support member and where the end part of the outer skin of the endoscope is arranged to be fixed by fixing means, in which part of the endoscope outer peripheral side of the above described optical part holding fixture is cut off, and to this cut-off part, part of the mounting hole wall of the above described support member is extended out, and the outer peripheral recess of the above described support member is deeply formed (diameter is reduced), and consequently, the swell of the outer skin fixing part is eliminated.
In the above description, it is preferable that the end part of the above described outer skin is bound to the above described recess with a string that is the above described fixing means, and that adhesives are applied on that string winding part.
According to the above described configuration, the step part for fixing the outer skin of the support member can be made deep by the notch of the optical part holding fixture, that is, the diameter can be reduced, and the outer skin end part can be arranged at this step part with a reduced diameter, and therefore, even in the case where this outer skin is fixed by string winding and adhesives are applied, it is possible for the swell at this part to be eliminated or to be made extremely small.